1. Field of the Invention
This invention pertains generally to gas lamps and more particularly with ultra low power devices for reducing or increasing the flow of gas to a lamp under the control of a solar battery. In particular, the invention pertains to electrically operated gas valves used in such applications.
2. Description of the Prior Art
Gas lamps have been in use for well over one hundred years for municipal or commercial lighting and almost as long for residential lighting. Originally, lamps were operated from gas derived from coal or oil. Due to the limited production capacity and subsequent high cost of the gas, lamps were extinguished and relit every night by hand. When the gas supply grew and drove costs down, it was found to be less expensive to leave the lamps burning all day as opposed to paying a lamp lighter to control them.
In the 1970s, the energy crisis drove prices of fuels up greatly. Many people abandoned the use of gas lamps due to the now high operating costs, and for a time a federal prohibition existed against their use to save natural gas.
Several devices have been marketed to save gas during daylight hours. Some of these devices used dry storage batteries and electronics to extinguish and relight the lamps. Other devices employed solar batteries and "snap-action" valves to extinguish the lamps. Snap-action valves abruptly open or close gas flow, rather than transitioning the flow between a high flow rate and a low flow rate.
All of the aforementioned devices are relatively expensive and unreliable. The battery operated devices described above had the added disadvantage of requiring frequent battery replacement. Such devices typically make use of snap-action valves to reduce their electrical requirements. These snap-action valves had the unwanted side effect of occasionally destroying the mantel of the gas lamp. Occasional damage to the gas lamp mantel occurs because the igniter may fail to relight the gas or the battery running the igniter may lose its charge or require replacement. Furthermore, the snap action relight devices would often blow out the pilot flame. If reignition fails to occur for any reason, gas pressure will increase in the mantel head causing the mantel head to break. In addition to these problems, the battery operated relight type devices can have a danger of cracking the mantel head due to the force caused by the ignition of the gas.
An example of such a snap-action relight type device is described in U.S. Pat. No. 4,830,606 to Dillinger. The device of Dillinger utilizes a solar cell, a rechargeable battery, and an electromagnetic gas valve operatively connected to a gas supply and to a mantel head. When solar energy is received at the solar cell, the electromagnetic valve is closed and the igniter is turned off. When a diminished level of light is received at the solar cell, the gas valve is opened and energy is sent through the igniter to cause a discharge spark to ignite the now flowing gas.
Therefore, a device is needed to reduce the flow of gas to a lamp during increased ambient light conditions and to increase the flow of gas during decreased ambient light conditions. Such device should not employ snap acting valves or dry storage batteries. Rather, such a device should be capable of being smoothly throttled between high gas flow rate and low gas flow rate.